Lewis electron-dot symbols together with the
noble gas rule can be used to predict the kinds of ions that
emerge from the elements - "monatomic" ions. The idea
is that elements will tend to gain or loose electrons in such
a way that they will have an octet (eight) valence electrons
leaving a lewis dot symbol with 8 electrons around it. This rule
applies to the alkali, alkali earth and main group elements.
It obviously does not apply to H, He, Li, Be, and B since these
elements have too few electrons to consider octets. In these
latter cases the helium noble gas configuration applies.

Examples of Simple Ions

In the above diagram, when Li, Be and Ca loose their electrons
the "new" valence electrons in the ion are drawn in.

These elemental ions are stable in the sense that they will
not readily gain or loose electrons. However, since they are
charged they can combine electrostatically to form ionic bonds.
the resulting compound is called "ionic" or "salt",
e.g., Ca+ + 2Cl- ---> Ca(Cl)2 = calcium chloride.